1. Field of the Invention
The invention concerns a method to detect tumorous cell tissue in the gastrointestinal tract with the use of an endocapsule.
To detect carcinomas of the gastrointestinal tract—for example in the course of a stomach endoscopy—tissue samples are extracted and examined for the presence of a carcinoma. A number of biopsies are frequently required. In order to reduce their number, a procedure known as auto-fluorescence endoscopy is used in which the fluorescence of substances inherent to the body is utilized, which substances occur in an increased concentration in malignant tissue due to increased metabolic activity. An additional possibility for biopsy control is the application of endomicroscopy, i.e. an examination with the aid of a microscope integrated into an endoscope, wherein a contrast agent must be administered to the patient to stain the tissue. However, biopsies continue to be necessary in both cases.
The extracted tissue samples are histologically examined in a laboratory. For example, slices are produced from the deep-frozen tell tissue samples, which slices are then assessed by the pathologist. A high time cost is necessary for this since not only the sample preparation, but rather also the documentation and the transport require time. Wait times also cannot be avoided. The results are often only present a few days later, which leads to a large psychological stress for the respective patient.
In addition to the aforementioned assessment of tissue samples, it is also known to conduct a fluorescence cystoscopy for a tumor diagnosis. Tumorous cell tissue is thereby made light-sensitive with suitable chemical substances, and fluorescence at the cells prepared in such a manner is excited upon exposure with light. The light for excitation has a different color than the fluorescence light. However, the substances that are used are strongly phototoxic and can cause necrosis at the correspondingly treated tissue. This can also be utilized for a therapy against carcinomatous tumors, but the knowledge of the positions and the propagation of tumorous cell tissue is required.
A technique known as 5-ALA induced detection (in which 5-aminolevulinic acid is injected), or methods that are commercially known as Hexvix and TOOKAD and in which other photoactive substances are used, are used to detect tumorous cell tissue.
It is disadvantageous that substances that are stressful to the respective patient immediately (but also subsequently over a longer time period) must be introduced into the body of the patient. After the injection of the substances, the examinations cannot be implemented immediately afterward since a reaction time (that can vary from patient to patient) must elapse.
A method for a laser-induced fluorescence of tissue is moreover known from DE 689 25 586 T2, in which method it should be possible to conclude the respective cell tissue type via a fluorescence excitation and the detection of specific characteristic wavelengths in the detected wavelength spectrum of the fluorescence light.
However, it has been shown that the inherent fluorescence of the body's own chromophores that can be excited to fluorescence in cell tissue (that can be tumorous or healthy) using the occurrence of a wavelength (or possibly also multiple wavelengths) that occur in the fluorescence light spectrum is not unambiguous since a cooperative response of the examined cells cannot be disregarded. These different factors and the biomolecular cell structure have a strong influence, and an association as to whether it is healthy or tumorous cell tissue is not possible with sufficient certainty.